MPC
Research Projects (2008-09)

Identifying Number

MPC-276

Project Title

Use of Salvaged Utility Poles in Roadway Bridges, Year 3

University

Colorado State University

Project Investigators

Richard M. Gutkowski and Jeno Balogh

Description of Project Abstract

Nationwide, many bridges are in a state of agedness, disrepair, and structural and/or functional deficiency. In rural settings, county jurisdictions have numerous inventoried bridges in such condition by very limited funds for repair/replacement. Only a very small proportion can ba addressed annually. Numerous bridges shorter than 20 ft long exist as well, especially over streams and ditches on agricultural land, or in state and national parks. Sub-20 ft bridges are not eligible for federal bridge infrastructure funds, so are frequently, if not commonly, neglected. Thus, innovative low material cost bridges which are readily built by unskilled labor are a boon to small rural jurisdictions and on park lands.

This ongoing project involved conceiving and configuring a composite bridge comprised of concrete and wood utility poles. The ease of construction will make the bridge a feasible alternative for use in short to medium span bridges in rural secondary road settings and off highway gravel roadways. The concept is to use of utility poles as either individual stringers or a solid deck beneath a conventional reinforced concrete bridge deck. Frequently, wood utility poles are replaced as part of secondary road reconstruction, such as widening roadways. Many of the removed poles are still sound structurally and usable. Instead of discarding these members it is worthwhile to consider viable alternatives uses. Since utility poles are commonly 40-60 ft long, sometimes longer, they can be a low cost recycled resource for short and medium span bridge construction. Conceiving such uses in which salvaged utility poles are used enables a large supply of poles to be re-used. Indeed, the PI readily accomplished a donation of the utility poles from the utility company for use in this project, suggesting a possible future low cost or no cost material source.

Project Objectives

The objective of this project is to develop the configuration of a roadway bridge using an innovative layered concrete-wood utility pole concept and test pertinent beam specimens under ramp loading, repeated loading and creep loading.

In preceding successful work, the concept was developed into a preliminary beam configuration (via a proposed design code methodology and equations) and two narrow beam specimens (representative of a full bridge cross section) were laboratory load tested to failure under ramp loading. Composite action achieved was extremely high, approximately 95% degree of efficiency. For the proposed continuation project load testing under repeated and creep loading is planned.

Project Approach/Methods

The prior work consisted of the beam testing mentioned above. To make the specimens, the tapered utility poles were place in alternative directions at slight incline to incorporate camber, and topped with a structural concrete layer. A solid layer of poles is involved in a bridge application, thus two poles side by side laterally interconnected mechanically was the configuration examined. Only work in Switzerland was found as related to use of round poles in wood-concrete bridge construction, with an actually bridge having been constructed. A notched shear key-anchor type of interlayer connection was incorporated. This detail has been examined in past CSU research on wood-concrete sstems not involving utility poles, and it performs well. Fundamental equations of mechanics were developed and used to size the specimens. Load testing was highly successful, showing the ultimate load capacity was consistent with code requirements and a progressive ductile failure occurred with a plateau and of resistance and no collapse. Results are reported in MPC Report cited below.

In a recent MPC supported workshop (apart from this project) held at CSU for county road and bridge engineers, international experts in wood-concrete floor and bridge engineers, international experts in wood-concrete floor and bridge construction gave summary presentations of their research and applied work. Researchers participated from Brazil (experience in use of low quality salvage material), New Zealand (rigorous computer modeling of long-term effects, such as creep and shrinkage), and Portugal (interconnection methods and computer models), and Sweden (prefabricated floor systems). Each of the researchers employs different inter-connection methods than each other, some examining a notched shear/key but without an anchor. Also, their applications were mostly not for bridges. Portuguese researchers at the Technical University of Coimbra had implemented a wood-concrete bridge construction in a successful pilot project on a forestry logging road. R. Gutkowski previously visited that bridge site to observe the completed bridge and discuss its performance with the research team. Utility poles were not used and the wood layer was spaced individual glue-laminated timber beams, not a solid layer. However, in a recent second visit, he presented the above successful work at CSU. Portuguese researchers indicated an interested in the CSU concept and pursuing a possible application in new round-pole construction. They were conducting preliminary analytical studies and pursuing a likely research funding path in Portugal including a possible field bridge application. Apart from this work, researchers in New Zealand/Italy are jointly conducting cyclic load tests of wood-concrete beams to 2,000,000 load cycles. CSU is also conducting analytical studies of long-term behavior due to exposure, creep, etc. using 3-D finite element analysis (FEA) and to be supported by the load tests proposed herein in exposed conditions.

Based on development to date, the anticipated tasks in the continuation study are:

For the planned continuation study, additional utility poles are available from the previous donation of them. Two specimens are anticipated. One specimen will be subjected to long term loading consistent with an estimated long term load level for field conditions on low volume roads. Another will be loaded with a repeated load of magnitude and number of cyclers determined from ultimate capacities observed in the preceding ramp load tests, appropriately factored down to a rational service load level.

• Task 1 – Complete the 3-D FEA computer modeling for short term and long term effects of loading and exposure conditions (creep, shrinkage etc.) for beam specimens.
• Task 2 – Using mechanics – and design code based approach already developed configure two layered specimens comprised of a solid wood layer of poles with interlayer connection, similar in configuration of those studied by LeBorgne and Gutkowski.
• Task 3 – Load test the first specimen under long term loading and compare the performance of the specimen with the 3-D analytical model prediction of its behavior. Long term loading would be in exposed conditions for approximately 6-9 months.
• Task 4 – Load test the second specimen under repeated load of magnitude equal to the estimated service load level based on the results of LeBorgne and Gutkowski. Compare the performance with the prior ramp load tests.
• Task 5 – Develop an MPC research report on the findings.

MPC Critical Issues Addressed by the Research

This work addressed USDOT Strategic Goal – Infrastructure Management (and Environmental Stewardship): (1) Improved Infrastructure Design, (2) Infrastructure Longevity, and (3) Infrastructure that Minimizes Environmental Impacts.

Contributions/Potential Applications of Research

Much of rural America has low tax base communities dependent on agricultural economies and related freight and shipping industry. State and federal parks face tight budgets for daily operations and maintenance overall and especially for road and bridge systems for short to medium span situations on secondary roads is helpful in these situations. As stated above, examples of recently constructed layered w/c bridges using round poles exist in Switzerland, including one with round roles. Also, a 55 ft span w/c stringer bridge was built with glue-laminated wood beams in Portugal. These successful overseas examples lend credibility to the above concept as being practically plausible, feasible and economical. Implementation of an actual field bridge project is envisioned, but as a task pursued subsequent to the project.

Technology Transfer Activities

An innovative bridge concept will be configured. A written MPC report and TLN teleconference seminar are planned for dissemination of the results. A potential future pilot bridge construction is envisioned (with presently undetermined timing) after this project concludes, potentially in Portugal in cooperation with the Portuguese researchers.

Time Duration

July 1, 2008 - June 30, 2009

Total Project Cost

$28,283

MPC Funds Requested

$14,860

TRB Keywords

Bridges, composite, wood-concrete, long-term loading, repeated loading

References

• Gutkowski, R.M., W. Thompson, K. Brown, P. Etournaud, A. Shigidi and J. Natterer, 1999. “Laboratory Tests of Composite Wood – Concrete Beam and Deck Specimens.” Proceeding of “1999 RILEM Symposium on Timber Engineering”. Stockholm, Sweden.
• Gutkowski, R.M., E. Koike, P. Etournaud, and J. Natterer, 1999. “Laboratory Tests of Composite Wood – Concrete Beam and Deck Specimens.” Proceedings of “STRUCTURAL FAULTS + REPAIR” – 99, 8th International Conference and Exhibition, London, England.
• Gutkowski, R.M., J. Balogh, J. Natterer, K. Brown, E. Koike, and P. Etournaud. 2000. “Laboratory Tests of Composite Wood – Concrete Beam and Floor Specimens.” Proceedings of the World Conference on Timber Engineering – 2000, Whistler Resort, B.C., Canada: Department of Civil Engineering, Department of Wood Science: School of Architecture, University of British Columbia, Vancouver, Canada.
• Gutkoski, R.M., J. Balogh. 2001. “Refined Modeling of Composite Wood-Concrete Beam and Deck Specimens,” Proceedings, 9th International Conference and Exhibition in Structural Faults and Repair – 2001, ASCE, London, UK.
• Gutkowski, R.M., Brown, K., Etournaud, P. and Thompson, W. 2001. “Shear Key for Strengthening Bridges,” MPC Report No. 01-126, Mountain Plans Consortium, North Dakota State University, Fargo, N.D.
• Balogh, J. Wieligmann, M., Gutkoski, R., P. Haller. 2002. Stress-Strain Behavior of Connections for Partially Compost Wood-Concrete Floors and Deck Systems, Proceedings – 2nd Material Specialty Conference of the Canadian Society of Civil Engineering, Montreal, Quebec, Canada.
• Gutkowski, R., Balogh, J. Rogers, C., SaRibeiro, R. 2002. Laboratory Tests of Deep Composite Wood-Concrete Beam and Eck Specimens, Proceedings – 4th Structural Specialty Conference of the Canadian Society of Civil Engineering, Montreal, Quebec Canada.
• Balogh, J., Gutkowski R.M., Wieligmann, M. and Haller, P. 2002. Mechanics behavior of dowel connectors for partially composite wood-concrete beam. Proceedings, the 7th World Conference on Timber Engineering, Selangor, Malaysia, Mara University of Technology, Vol. 3.
• Gutkowski, R., Balogh, J., Rogers, C., and Shigidi, A.M.T. 2002. Load test of composite wood-concrete deep beam specimen. Proceedings, The 7th World Conference on Timber Engineering, Selangor, Malaysia, Mara University of Technology, Vol. 3.
• Ceccotti, A., Fragiacomo, M., and Gutkowski, R. 2002. Design of Timber-Concrete composite structures according to EC5 – 2002 version. Proceedings of 35th Meeting of Working Commission W 18 – Timber Structures, Kyoto, Japan. International Council for Research and Innocation in Building and Construction, Lerhstuhl for Ingeiieurholzbau und Baukonstructionen, Universitat Karlsruhe, Germany.
• Gutkowski, R., Balogh, J., Wieligmann, M., Wieligmann, M., Rogers, C., and Haller, P. 2003. Analysis and Testing of Composite Wood-Concrete Floor/Deck Systems. Proceedings of CMEM 2003, Eleventh International Conference on Computational Methods and Experimental Measurements, Halkidiki, Greece, WIT Press, Wessex Institute of Technology, UK.
• Fast, R.S. 2003. “Durability Studies of Layered wood-concrete Composite Connections and Beams,” Structural Research Report No. 84, Colorado State University
• Gutkowski, R.M., Brown, K., Shigidi, A., and Natterer, J. 2003. Investigation of Notched Composite Wood-Concrete Connections. Journal of Structral Engineering, ASCE, Reston, VA, 130 (10) pp 1553-1561.
• Rogers, C., Gutkoski, R., and Balogh, J. 2004. “Load Tests of Large Wood-Concrete Beams,” MPC Report NO 04-165, Mountain Plains Consortium, North Dakota State University, Fargo, N.n.
• Fragiacomo, M., Gutowski, R.m., Balogh, J., and Fast, R.s. 2006. “Long-term behaviour of wood-concrete composite beams with notched connection detail.” 9th World conference on Timber Engineering WCTE 2006, Portland (U.S.A.(, August 6-10, 8 pp., CD.
• Gutkowski, R.M., Fragiacomo, M., Balogh, J., and Fast, R. 2006. Time-Dependent Performance of Notched Wood-Concrete Composite Beams, “Proceedings, 11th International Conference and Exhibition in Structural Fualts and Repair – 2006, Edinburgh, Scotland.
• Fragiacomo, M., Gutkowski, R.M., Balogh, J., and Fast R.S. 2007. “long-term behavior of wood-concrete composite floor/deck systems with shear key connection detail.” Journal of Structural Engineering, ASCE, Vol. 133, No.9, pp. 1307-1315.
• Gutkowski, R.M., Brown, K., Shigidi, A., and Natterer, J. 2007. Laboratory Tests of Composite Wood-Concrete Beams, Construction and Building MATERIALS, Elsevier Ltd., Edinburgh, Scotland.
• Balogh, J., Fragiacomo, M., Gutkowski, R.M., and Fast, R.S. 2007. “Influences of Repeated and Sustained Loading on the Performance of Layered Wood-Concrete Composite Beams.” Journal of Structural Engineering. ASCE.
• LeBorgne, M., and Gutkowski, R. 2008. Load Testing of Wood-Concrete Beams Incorporating Recycled Utility Poles. MPC Report No. 08-197. Mountain-Plains Consortium, North Dakota State University, Fargo, N.D.
• LeBorgne, M., and Gutkowski, R.M., Accepted for Publication. “Effects of various admixtures and shear keys in wood-concrete composite beams.” Construction and Building Materials, Elsevier Publications, Edinburgh, Scotland.